Disk-type memory devices are typically manufactured having a single actuator assembly mounted within the industry standard disk drive enclosures. The actuator assembly typically has a read/write head mounted at a distal end for reading optically encoded data, optically/magnetically encoded data, or magnetically encoded data from a rotating disk or platter mounted on a disk hub or spindle. Data writes to a disk drive with a single actuator with one read/write head per disk allows for only one write or read from the platter at a time, which limits the amount of data that can be transferred between the platter and a host system.
Many conventional data storage systems consist of one or more storage platters with a single actuator arm for reading and writing data from/to the tracks and sectors of the platter. All read/write heads of the actuator must move as a single unit and can only access the same sector and track of each disk simultaneously, which requires the actuator to physically move its location to access data on a different track. As a result, data access delays are produced in conventional single actuator data storage systems.
Memory devices for storing magnetically encoded data and having multiple actuator assemblies are present in the art. For example, U.S. Pat. No. 5,081,552 (Glaser et al.), describes a rigid magnetically encoded data disk with a disk drive head assembly having a pair of actuator assemblies. Unfortunately, as is the problem with other attempts at providing a multiple actuator disk drive, the Glaser et al. disk drive requires at least two different and distinct transducer heads. The special transducer heads of Glaser et al. are expensive to manufacture.
U.S. Pat. No. 5,343,345 (Gilovich) and U.S. Pat. No. 5,343,347 (Gilovich) also describe a disk drive transducer head assembly having multiple actuators, which requires at least two different and distinct transducer heads unless, in the case of two actuators, the actuators are positioned in diagonal corners.
U.S. Pat. No. 6,057,990 (Gilovich) describes a data storage device having a first data storage disk and a first actuator arm assembly having at least one arm. Each of the arms have a distal end carrying a read/write transducer head for reading information from and writing information to only the first data storage disk. The data storage device comprises a second data storage disk and a second actuator arm assembly having at least one arm. Each arm has a distal end carrying a read/write transducer head with the read/write transducer head reading information from and writing information to only the second data storage disk.
U.S. Pat. No. 6,563,657 (Serrano) describes a hard disk drive for a computer system having at least two actuators for reading data from or writing data to the disks. The actuators may be configured to support the different methods of data access required of them. For example, if large quantities of sequential data are performed, one operation uses both actuators to increase throughput. However, if mostly random operations are to be performed, then independent usage of the actuators is preferred. These two methods of usage can be supported simultaneously and dictated by the user. The tracking format of the actuators can be configured such that the next logical track is physically located under a head on a different actuator to improve sequential operation. The actuators also may be utilized in a dual-channel configuration so that data can be written to both actuators at the same time, or read back at the same time to improve throughput. In addition, either of these configurations can be selected on a transfer-by-transfer basis by the user. However, as described in Serrano, the multiple actuators are mounted to a common shaft of a single pivot cartridge assembly. Each actuator comprises a plurality of stacked, parallel actuator arms in the form of a comb that is pivotally mounted to a base about a pivot cartridge assembly. In this configuration with multiple actuators mounted to a common shaft, each actuator is travelling the full radius of the disk and incurring maximal seek times. Further, because the multiple actuators mounted to a common shaft, individual actuators cannot be positioned at different locations around the disk.